A conventional probe apparatus includes a main body, a mounting table arranged to be movable in directions of X, Y, Z and ⊖ within the main body, on which an object to be tested (for example, a semiconductor wafer) is mounted, a probe card having a plurality of probes to be brought into contact with a plurality of electrode pads of the semiconductor wafer mounted on the mounting table, a head-plate to horizontally support the probe card, and an alignment device to implement position alignment of the probes and the semiconductor wafer on the mounting table. In the conventional probe apparatus, after the electrode pads of the semiconductor wafer and the probes are aligned with each other, signals are transmitted between the probes of the probe card, which is electrically connected to a tester via a test-head and a connection ring, and the electrode pads of respective devices provided in the semiconductor wafer, thereby implementing electric characteristic test of the respective devices.
The semiconductor wafer, for example, as shown in FIGS. 6A to 6C, may come into electrical contact with the probes of the probe card, to implement electric characteristic test. More specifically, as shown in FIG. 6A, once the semiconductor wafer W, mounted on the mounting table 1, reaches a position immediately under the probe card 2, the mounting table 1 is moved upward to allow the electrode pads (not shown) of the semiconductor wafer W to come into contact with the corresponding probes 2A as shown in FIG. 6B. Then, as the mounting table 1 is overdriven from the position shown in FIG. 6B to a position shown in FIG. 6C where the semiconductor wafer W comes into contact with the probes 2A with a predetermined load, the electrode pads of the semiconductor wafer W comes into electrical contact with the probes 2A. In this case, the tester implements transmission and reception of signals with the electrode pads of the semiconductor wafer W via the probes 2A, thereby sequentially implementing electric characteristic test of the devices. The probe card 2, as shown in FIGS. 6A to 6C, is adapted to come into contact with all the electrode pads of the semiconductor wafer W at once. In such a contact state of the probe card 2, for example, electric characteristic test is implemented on all the devices plural times on a “per a predetermined number of devices” basis. In FIGS. 6A to 6C, reference numeral “3” indicates the head-plate used to horizontally support the probe card 2.
However, in the above-described conventional probe apparatus, when the mounting table 1 is overdriven by a preset distance while the semiconductor wafer W is in contact with the probes 2A, considerable contact load may be exerted between the semiconductor wafer W and the probes 2A. The contact load, for example, as shown in FIG. 6C, causes a central portion of the head-plate 3 to be slightly upwardly deformed, resulting in upward displacement of the probe card 2. Accordingly, even if the mounting table 1 is overdriven by the preset distance, the head-plate 3 is deformed from a position as shown in the left half of FIG. 7 to a position as shown in the right half of FIG. 7, thus causing the probe card 2 to be displaced upward by, e.g., about 10% to 20% of the overdrive amount of the mounting table 1. For that reason, an originally required overdrive amount (e.g., about 100 μm) may not be accurately applied to the mounting table 1, and also a good electrical contact state may not be guaranteed, which may deteriorate the reliability of the test. Especially, when test is performed in a state where the probes 2A of the probe card 2 are required to be brought into contact with respectively corresponding devices of the semiconductor wafer W at once, the deformation of the head-plate 3 may affect the test greatly.
As for a technique related to an overdriving, there are suggested techniques disclosed in Patent Documents 1 to 3. In the technique of Patent Document 1, there is provided an optical length-measuring machine for measuring a vertical displacement of a probe card. A lifting amount of a mounting table is regulated based on the displacement of the probe card measured by the optical length-measuring machine, and the semiconductor wafer and the probe card are brought into contact with each other by a proper overdrive amount. In the technique of Patent Document 2, an overdrive amount of a mounting table can be appropriately set by accurately detecting a displacement of a probe card deformed due to the overdrive of the mounting table. Both these techniques obtain an appropriate overdrive amount of a mounting table by eliminating the effect caused by deformation of the probe card or sagging of the mounting table, but may not cope with deformation of interface parts including the probe card and the head-plate during test. In addition, in the technique of Patent Document 3, a stopper is provided at a side of a chuck top, to manage a predetermined overdrive amount, thereby preventing a probe card or a head-plate from being deformed by heat transmitted from the chuck top and eliminating any negative effect on the overdrive amount.
[Patent Document 1] Japanese Patent Laid-open Publication No. 2004-265895
[Patent Document 2] Japanese Patent Laid-open Publication No. 2003-050271
[Patent Document 3] Japanese Patent Laid-open Publication No. 2005-049254